Mix Dry Ingredients: Add the all-purpose flour, almond flour, powdered sugar, and salt to a food processor and pulse a couple of times just to combine the dry ingredients evenly.
1 cup all-purpose flour, 3 tablespoons almond flour, ½ cup powdered sugar, ⅛ teaspoon salt
Cut In Butter: Add the cold, cubed butter and pulse a few times until the mixture looks sandy, with tiny specks of butter still visible.
4 ½ tablespoons unsalted butter
Add The Egg: Pour in the whisked egg and pulse a few more times until the dough is roughly combined; it should remain uneven and crumbly at this stage.
½ large egg
Finish the Dough: Transfer the mixture to a bowl or clean work surface and quickly press it together by hand until it forms a dough, working fast so the butter stays cold.
Chill the Dough: Wrap the dough in plastic or a bag and flatten slightly into a disk so it chills faster and hydrates evenly; refrigerate for at least 1 hour, or ideally overnight.
Roll and Freeze: Roll the dough to about 3 mm on lightly floured parchment or a silicone mat, turning it every couple passes and adding a little flour if it sticks; once rolled, freeze 15 to 30 minutes until slightly firm but still flexible.
Transfer to Tart Pan: Lightly butter the tart pan if it’s not non-stick, then drape the chilled dough over the pan so it sits evenly across the base and sides.
Press Into Pan: As the dough warms slightly, gently press it into the bottom and sides, making sure it fits into all corners, especially where the base meets the sides.
Trim and Dock: Trim excess dough by cutting from the inside edge outward with a sharp knife, press the edges again so the crust adheres, then prick the bottom a few times with a fork.
Freeze Before Baking: Freeze the shaped tart shell for about 30 minutes to help it hold its shape during baking.
Bake the Shell: Bake at 180°C (355°F) for 15–18 minutes, or until the edges are lightly golden, then let the tart shell cool completely in the pan before filling.